Problem running Window Manager after Sudo on Solaris

Hi List,
I have a typical problem where after i login into the console and then when
i sudo as another user and run window manager , it just kicks me out. I am
trying this on Solaris 2.5.1. The reason i need to do is different users use
different window managers, and i want to get to his window manager after i
sudo. I tried setting the DISPLAY etc but doesn't help.
Is there any workaround to fix this issue with Sudo or is this a Security
feature with Solaris.
This works just fine for me on SunOS 4.1.4 .
Thanks